1. Field of the Invention
The present invention relates to an electronic apparatus that is installed outdoors for use and is equipped with a light emitting diode for indicating a state of operation.
2. Description of the Related Art
Recently, a light emitting diode (LED) that is a type of semiconductor element that emits light by passing electric current has been rapidly expanded and continuing to become ubiquitous. Since the LED has features of long life, power saving, high luminance and the like, it is used in many electronic apparatuses for indicating a state of operation of the apparatuses.
For example, a plurality of LED's are disposed inside an apparatus so that a user can check whether or not power supply, communication and the like are normal by viewing light emission of each LED from the outside.
However, there is a case where a plurality of LED's are aligned inside an electronic apparatus, and light emission of a LED leaks into a neighboring LED. In this case, when a user views them from the outside of the apparatus, it is difficult to tell which LED emits light depending on a state of ambient light.
Therefore, a technique is proposed for preventing the light emission leak of LED's by disposing a component as a light shield between neighboring LED's of the plurality of LED's.
For example, Japanese unexamined patent publication No. 01-165182 discloses a light emitting diode display device having a structure including a lens guiding light from a plurality of LED and light shield walls disposed so as to penetrate the lens, so that each light emission is shielded by the light shield wall between neighboring LED's.
Japanese unexamined patent publication No. 11-024608 discloses an LED display device having a structure including light guide pipes, for individual LED's, made of a light guide member and a light shield member, the light guide pipes being coupled to each other and disposed between the LED and a display surface, so that light emission leak is prevented between neighboring LED's.
In addition, a conventional electronic apparatus with LED's is proposed as follows, which is a base station apparatus installed outdoors for use in mobile communication.
FIG. 11 is a cross section showing an inner structure of a conventional base station apparatus 9 at the vicinity of the bottom surface.
The base station apparatus 9 includes a cabinet body 93, a lid body 94, a printed circuit board unit 95, a sub circuit board unit 96, and a variety of other components.
The cabinet body 93 includes a peripheral wall like a rectangular cylinder and a bottom plate portion (not shown) that is fixed to one opening portion of the peripheral wall. The cabinet body 93 houses the printed circuit board unit 95, the sub circuit board unit 96 and a variety of other components constituting the base station apparatus 9.
The printed circuit board unit 95 has various electronic components such as an LSI (or a semiconductor integrated circuit element, not shown) on its surface and is fixed to the cabinet body 93 with a mounting bracket 102.
The sub circuit board unit 96 has LED's 97 on its surface and is fixed to the cabinet body 93 with a mounting bracket 103. The sub circuit board unit 96 is connected electrically to the printed circuit board unit 95 via a wiring cable 104. Each of the LED's 97 is covered with an opaque plastic component 105 having a cylindrical shape.
The lid body 94 is formed in a plate having a rectangular shape viewed from the front and fixed with screws (not shown) so as to close an opening of the cabinet body 93. The lid body 94 has a display panel 98. The display panel 98 is provided for checking light emission of the LED's 97 from the outside of the base station apparatus 9.
Note that the sub circuit board unit 96 is disposed separately from the printed circuit board unit 95 in order to dispose the LED's 97 close to the display panel 98 so that visibility of light emission of the LED's 97 can be improved.
The display panel 98 has a plate-like body 106 and a pressing member 107. The plate-like body 106 is made from transparent acrylic and covers an opening hole 108 formed in the lid body 94. The pressing member 107 is disposed in contact with a surface of the plate-like body 106 and attached to the lid body 94 with screws (not shown) so as to press the plate-like body 106. The pressing member 107 has a plurality of holes 109 for guiding light from the LED's 97 individually, in accordance with the number of LED's 97.
In this example, the plastic components 105 covering the LED's 97 and the holes 109 formed in the pressing member 107 of the display panel 98 guide light from the individual LED's 97 with the light prevented from being diffused, so that light of the LED's 97 are displayed individually on the surface of the lid body 94.
According to this structure, light emission of the LED's 97 disposed inside the base station apparatus 9 can be viewed externally.
However, the conventional electronic apparatus equipped with LED's described above needs, like the base station apparatus 9 shown in FIG. 11, not only the printed circuit board unit and the LED's but also the plastic component for preventing diffusion of light emission, the sub circuit board unit, the mounting bracket of the sub circuit board unit, the wiring cable between the printed circuit board unit and the sub circuit board unit, and the like. Therefore, there is a problem that the structural components increase and the structure inside the apparatus becomes complicated.
This problem probably occurs similarly in the case where the light emitting diode display device disclosed in Japanese unexamined patent publication No. 01-165182 is used for the electronic apparatus.
In addition, the base station apparatus or the like for mobile communication is often installed outdoors, so it is required to have a structure of sealed cabinet where water proofing property is considered. Therefore, there is a problem that accumulation of tolerances of individual components and attachment errors thereof may cause difficulty in matching positions of individual LED's with positions of corresponding holes formed in the display panel on the surface of the cabinet for registration. In addition, there is another problem that the sealed structure makes it difficult to correct the attachment position after the cabinet is sealed.
This problem probably occurs similarly in the case where the LED display device disclosed in Japanese unexamined patent publication No. 11-024608 is used for the electronic apparatus.